Process of obtaining alkali-metal compounds from silicates containing the same.



' UNITED STATES PATENT OFFICE;

ANTON MESSERSCHMIT T, OF STOLBERG, GERMANY.

rnociass. or OBTAINING ALKALI-METAL COMPOUNDS mom sxmcarss oomamme THE awn.

No Drawing.

To all whom it may concern Be it known that I, ANTON Messianscgnfl'rr, a subject of the German Emperor, residing in the city of Stolbcr Rhine Province, Germany, have invente new and useful Improvements in Processes of Qbta ning Alkali-Metal Compounds from silicates Containing the Same, oi? which the following is a specification.

This invention relates to a method for ex tracting pure alkali compounds from s1l1- cates containing alkali-metals compounds.

In silicate fiiineralscontaining alkali compounds, as feldspar, phonolite, mica, trass, etc-., potassium never occurs pure, but always in connection with sodium. While in feldspars for instance theamount of potassium contained therein exceeds t h atrno f sodium, this proportionis-iifieited in other minerals. When, therefore, such silicates are rendered soluble by treatment with suitable calcium or magnesium compounds, as

I for instance caustic lime, limestone. slime of calcium compounds, magnesia or the like, mixtures of potassium and sodium compounds are always produced. But these mixtures cannot be used in this form. A practical method for se arating them is not known so far. But sucli a method would be very important as pure potassium compounds are far more valuable than the corresponding sodium compounds. On .the' other hand a high degree of purity is required. The ditliculties in extracting pure alkali-metals compounds from minerals are still greater because the alkali-metals compoun s obtained are present in the resulting lye not only in the form of hydroxids, but often in considerable quantities as carbonates, aluminntes, silicates, and in some cases also as ma'nganatcs;

The object of the present invention is a method for separating the mixture of alkalimetals compounds into pure potassium and sodium compounds, said mixtures bein obtained by decomposing minerals containing silicates with lime-stone or other. calcium nitrate, or by treating said alkali metals compounds with nitric acid or nitro-gases,

Specification of Letters Patent.

Application filed April 6, 1912. Serial No. 689,049.

Patented Feb. 17, 1914.

all of which nitrating compounds I herein- .after refer to as nitratlng compounds.

Experiments have been made to obtain potassium in form of potassilnn nitra to from certain silicates containing potassium and which are soluble in acids, as for instance leucite by treating such minerals directly with nitric acid. But this method has the disadvantage that in addition to potassium, gother bases, especially aluminium com- Zpounds, iron oxid, magnesia, lime, etc., whicli occur in almost all natural minerals, are dissolved as nitrates. Largequantities of jelly-like'silicic acid are separated in this 1 process so that it is extremely dillicult to separate the soluble nitrates from'the insoluble residue, and .to isolate the nitrate of potassium from the excess of the compounds mixed therewith. These difficulties are fovercome according to the present invention in such a way that the a kali-nietals comounds are transformed wholly or. partly into nitrates. The method may be, for in stance, applied in such a manner that the lye obtained by decomposing the silicate-mm" erals is supplied with calcium nitrate in such .a proportion that the nitric acid present is exactly equivalent to the alkali-metals compounds in solution. The following reactions will then take place:

The sodium compounds are transformed, of courSc in the same way as the potassium compounds mentioned in the] ormulas above.

As stated before, other nitrates whose bases precipitate in alkaline solution not in the same manner as calcium nitrate, as for raq:

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cause the costs of evap orating can he saved acid is eliminated thereby. The nitro :5 can he r 'sorbed by any of the known n'icthods, preferably by treating the lusc-d silicate-calcium-niixture dry directly with nitro-gascs in a similar Way as in the known methods used for lime. By suspending the products of the reaction in Water the alkali-metals compounds are dissolved nitrates besides much into.

In practice it will he often difticult to detcrmine at once the equivalent. proportion of acid and base. Especially by using nitrogases it is almost impossible t interruptthe process of absorption when the desired proportion of acid and alkali obtained. A modification of the method is, therefore, that at first a part of the slime or the original l ye is treated with an excess of calm um nitrate, nitric acid or nitrogases and then slime or original lye is added until the desired proportion of acid and alkali-metals compounds produced. Thereby all other bases first. dissolved, as for instance calciuinmagnesiumiron-oxide, aluminium compounds, are again precipitated Whileonly potas ium nitrate and sodium nitrate, or g iotassium nitrate and sodium hydroxid stay in solution. Furthermore it was discovered that the insoluble residues of the method of ex tracting alkalimetals compounds from sili cate minerals could he used for an excellent The process of working up the residues for fertilizers has the great advantage that firstly the previously entirely useless products and es )ecially the lime con tained therein are rendered useful, and sec ondl y that the expensive nitrates do not need to bc Washed so carefully as would be necessary otherwise because this washing is a ditlicult operation on account of the quantity of the residue being extremely large in respect to the alkali-metals compounds. Therefore through omitting the careful washing, labor is saved and no nitric acid is lost. If instead of this nitrate-fertilizer containing all parts of the residue commercially pure calcium nitrate is to be prepared this can be done easily hy adding lime until the solution reacts nuti'al or alkaline. Therehyall bases together with silicic acid are precipitated while only lime as neutral, or basic calcium nitrate is in solution. The residue which is Washed by systematic lixiviation can be used for manufacturing clay prod ucts.

I claim:

1. The process of extracting alkali-metals compounds from silicates containing alkalimetals compounds, comprising treating the silicates to furnish a mixture of alkalimeta'ls compounds and converting the alkaliunetals compounds, comprising treatin metals compounds in the mixture into nitrates.

The process of extracting alkali metals compounds fromsiiicates containing alkalimetals compounds, comprising treating the silicates to furnish a mixture of alkalimetals compounds and converting the alkalimetals compoun(is in the mixture partially into nitrates.

The process of extracting alkali-metals compounds from silicates containing alkalimetals compounds, comprising treatin the silicates to furnish a mixture of a kalimetals compounds and adding substances containing NO iohS to the mixture.

4. The process (if extracting alkali-metals compounds from silicates containing alkali metals compounds, comprising treatin the silicates to furnish a mixture of a kali' metals compounds and adding a nitrating compound.

5. The rocess of extracting alkali'metals compoun s from silicates containing alkalithe silicates to furnish a mixture of a kalimetals compounds and adding substances containing NO -ions in an amount equivalent to the amount of the alkali-metals compounds in the mixture.

6. The process of extracting alkali-n1ctals compounds from silicates containing altlalimetals compounds, comprising treating the silicates to furnish a mixture of alkalimetals com ounds, adding. a substance containing N -ions to the mixture to convert the compounds into nitrates, and separating the potassium nitrate from the sodium compounds.

7. The process of extracting alkali-metais compounds from silicates containing alkalimetals compounds, comprising treating the silicates to furnish a mixture of alkali-metals compounds, converting the compounds into nitrates, and fractionally crystallizing the potassium nitrate from the mixture.

8. The process of extracting aikali-mctals compounds from silicates containing alkalimetals compounds comprising treating the silicates to furnish a mixture of alkali-metals compounds, converting the compounds into nitrates, adding potassium chlorid and separating the potassium nitrate from the sodium compounds.

9. The process of extracting alkali-metals compounds from silicates containing alkalimetals compounds, comprising treating the silicates to furnish a mixture of alkali-metals compounds, converting the compounds partially into nitrates, and fractionally crystallizing the potassium nitrate from the mixture.

10. The process of extracting alkali-metals compounds from silicates containing alkali-metals compounds, comprising treating the silicates to furnish a mixture of alkali- 

